1. Technical Field
This application claims a priority to Japanese Patent Application No. 2014-160182 filed on Aug. 6, 2014 which is hereby expressly incorporated by reference in its entirety.
Several aspects of the present invention relate to a solar cell, an electronic device, and a manufacturing method of a solar cell.
2. Related Art
A structure of a silicon-based solar cell which has been widely used is disclosed in JP-A-2014-096532. According to this, as a photoelectric conversion element, a single crystal silicon type photoelectric conversion element or a multi-crystal photoelectric conversion element is used. Then, a finger electrode which is a silver film is disposed on a light receiving surface of the photoelectric conversion element, and the finger electrode and a tab line are adhered to each other through a conductive adhesive material. As the tab line, a copper foil or an aluminum foil is used. A back electrode is disposed on a surface on a side opposite to the light receiving surface of the photoelectric conversion element. The back electrode is an aluminum film or a silver film, and is disposed by a sputtering method or a screen printing method.
A solar cell disposed in a portable electronic device is required to be thin and have high power generation efficiency. Therefore, a structure is considered in which a power generating film and a transparent conductive film are disposed on a metal plate of stainless steel or the like in an overlapping manner, and wiring is disposed on the metal plate and the transparent conductive film. The power generating film has a structure in which the metal plate is a back electrode, a p+ type layer, a p type layer, and an n type layer are laminated on the metal plate, and the transparent conductive film is connected to the n type layer. Alternatively, the power generating film has a PIN junction type structure in which an intrinsic semiconductor is arranged between the p type layer and the n type layer. Accordingly, the power generating film has a structure of a pn junction type photodiode. Then, when the power generating film is irradiated with light, the power generating film is excited by the light, and thus electric current flows.
The wiring is disposed on the transparent conductive film through the anisotropic conductive film. When the wiring is disposed, the power generating film, the transparent conductive film, and the anisotropic conductive film are pressed and heated by being interposed between the wiring and the metal plate, and thus the anisotropic conductive film functions as an adhesive material. The anisotropic conductive film includes conductive particles. When the power generating film is pressed, stress is concentrated by the conductive particles, and thus the power generating film is damaged. Accordingly, electrostatic resistance decreases. Therefore, a solar cell having excellent electrostatic resistance has been demanded.